Re: get_vmalloc_info() and /proc/meminfo insanely expensive

[Linus Torvalds]

On Thu, Aug 13, 2015 at 2:15 PM, Tony Luck <tony.luck@xxxxxxxxx> wrote:
>
> could you at least care enough to write that as
>
>       if (time_after(now, last + HZ)) {

Absolutely not. That would be wrong.

"time_after()" covers half the "unsigned long" space (very much on
purpose). We want the cached case to trigger _only_ for the much
tighter case of exactly 1000 jiffies.

                 Linus
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